A rotorcraft, such as a helicopter, includes a rotating rotor hub assembly that includes two or more rotor blades to generate lift and propulsion. While rotating, the rotor hub assembly has kinetic energy, which must be reduced during braking operations, such as when the rotorcraft lands. Rotorcraft brakes should also dissipate energy at a rate deemed acceptable by the pilot, but slow enough to prevent rotorcraft damage. Rotorcraft may have entire rotor brake subsystems devoted to reducing the rotational speed of the rotor hub assembly. For example, rotorcraft currently utilize disc-and-caliper braking systems, in which fluid pressure from a master cylinder drives caliper pistons onto brake pads, which clamp on a rotating disc, thereby producing friction that slows the rotor hub assembly. These existing systems are not unlike the disc brakes used on some automobiles.
Traditional braking systems, such as disc-and-caliper systems, however, have several drawbacks. First, disc-and-caliper systems add significant weight to the rotorcraft, increasing the amount of lift needed to fly the rotorcraft, thereby consuming more fuel and reducing rotorcraft endurance. Second, disc-and-caliper systems take up valuable space in the rotorcraft. Third, because they constitute an entirely separate subsystem, disc-and-caliper systems add complexity to the braking functionality of the rotorcraft. For example, disc-and-caliper systems may require sensors that ensure the caliper has released pressure after braking to prevent the heat generated between the brake pads and disc from causing a fire. Fourth, disc-and-caliper systems can be expensive, adding to the overall cost of the rotorcraft. Accordingly, a need has arisen for improved rotorcraft braking systems that reduce rotorcraft weight and are able to utilize existing components of the rotorcraft to achieve the braking functionality. A need has also arisen for improved rotorcraft braking systems that are smaller, safer, less expensive and do not contribute to the complexity of the rotorcraft in a detrimental way.